The present invention relates to a cathode arrangement with a large surface area comprising a consumable cathode plate that is connected to an intermediate plate with a high electrical and thermal conductivity and/or to a base plate whereby the arrangement is provided with cooling channels.
Such cathode arrangements are, for example, employed in coating apparatus and serve as a source for at least a portion of the material that provides the coating. Especially, cathode plates consisting of, for example, titanium, chromium, titanium-aluminum, titanium-zirconium, are employed for the coating of workpieces. When such coating apparatus are in operation the cathode plates are provided with large electrical currents in order to generate an electrical arc which, depending on the coating procedure, may be further biased by magnetic fields.
With the known coating processes and coating apparatus it has been a problem up to now to achieve a uniform consumption of the cathode plate. In general, the cathode plates are consumed in a non-uniform manner so that their service life is shorter than theoretically possible. Experiments in which the consumption behavior of the cathode plate has been subjected to various measures, for example, static magnetic fields, have resulted in improvements; however, the cathode plates are still consumed at a higher rate in individual areas.
It is therefore an object of the present invention to provide a large surface cathode arrangement with which a uniform consumption of the cathode plate is possible.